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Journal of Applied Physics : Phase transformation sequence and mag...

By: X. Y. Xiong and T. R. Finlayson

Description: The phase transformation sequence, microstructure and compositions, and magnetic properties for a melt-spun Sm(Co0.68Fe0.2Cu0.1Zr0.02)7.5 alloy after isochronal heat treatments have been studied by using x-ray diffraction, transmission electron microscopy, three-dimensional atom probe (3DAP), and magnetometry. The as-spun ribbons had a single phase with the Cu7Tb structure. After being aged at 720 °C, the single phase decomposed into two major phases: 2:17R ...

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Review of Scientific Instruments : A time-resolved single-pass tec...

By: Jun Li, Xianming Zhou, and Jiabo Li

Description: An experimental method was developed to perform time-resolved, single-pass optical absorption measurements and to determine absorption coefficients of window materials under strong shock compression up to ∼ 200 GPa. Experimental details are described of (i) a configuration to generate an in situ dynamic, bright, optical source and (ii) a sample assembly with a lithium fluoride plate to essentially eliminate heat transfer from the hot radiator into the specim...

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Applied Physics Letters : Restoration of high spatial frequency at...

By: Du Hyun Beak, Jin Woo Yoon, Jae Sung Shin, and Hong Jin Kong

Description: We have found experimentally that it is possible to restore the high spatial frequency of optical images by using stimulated Brillouin scattering (SBS) with a prepulse. The Stokes wave usually has to lose the high spatial frequency because of the necessary energy to generate the acoustic grating. However, this problem has been resolved by using a prepulse method. We have achieved an amplitude increase of ~41% compared to the normal SBS scheme at a spatial ...

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The Journal of Chemical Physics : The CCSD(T) complete basis set l...

By: Ericka C. Barnes, George A. Petersson, David Feller, and Kirk A. Peterson

Description: Recent estimates of the CCSD(T)(FC) limit for the neon atom (−128.8690±0.001 and −128.8687±0.0005 hartree) are refined. Re-examination of the basis set convergence of the separate self-consistent field, MP2-αβ, MP2-αα, CCSD–MP2, and (T) components of the valence CCSD(T) energy gives a complete basis set limit of −128.869 236±0.000 02 hartree. This can now be used as an improved benchmark to calibrate more approximate calculations.

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Journal of Mathematical Physics : Adiabatically switched-on electr...

By: H. D. Cornean, P. Duclos, G. Nenciu, and R. Purice

Description: Consider a three dimensional system which looks like a cross connected pipe system, i.e., a small sample coupled to a finite number of leads. We investigate the current running through this system, in the linear response regime, when we adiabatically turn on an electrical bias between leads. The main technical tool is the use of a finite volume regularization, which allows us to define the current coming out of a lead as the time derivative of its charge. We...

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Physics of Plasmas : Demonstration of detuning and wavebreaking ef...

By: N. A. Yampolsky, N. J. Fisch, V. M. Malkin, E. J. Valeo, R. Lindberg et al

Description: A plasma-based resonant backward Raman amplifier/compressor for high power amplification of short laser pulses might, under ideal conditions, convert as much as 90% of the pump energy to the seed pulse. While the theoretical highest possible efficiency of this scheme has not yet been achieved, larger efficiencies than ever before obtained experimentally (6.4%) are now being reported, and these efficiencies are accompanied by strong pulse compression. Based o...

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Journal of Applied Physics : Temperature dependence of voltage-con...

By: T. W. Hickmott

Description: Voltage-controlled negative resistance (VCNR) and unipolar resistive switching that can be used for memory applications can develop in the current-voltage (I-V) curves of metal-insulator-metal diodes. Electroluminescence is intimately connected with the occurrence of VCNR in I-V curves. The temperature dependence of VCNR and electroluminescence of Al–Al2O3–Au diodes with anodic Al2O3 thicknesses between 12 and 54 nm has been studied between 300 and 180 K. Th...

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Journal of Applied Physics : Low Schottky barrier height for ErSi2...

By: Nicolas Reckinger, Xiaohui Tang, Vincent Bayot, Dmitri A. Yarekha, Emmanuel Dubois et al

Description: In this paper, the formation of Er disilicide (ErSi2−x) with a Ti cap on low doping n-type Si(100) is investigated. After deposition in ultrahigh vacuum, the solid-state reaction between Er and Si is performed ex situ by rapid thermal annealing between 450 and 600 °C in a forming gas ambience with a 10 nm thick Ti capping layer to protect Er from oxidation. X-ray diffraction analyses have confirmed the formation of ErSi2−x for all annealing temperatures. The...

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Review of Scientific Instruments : Design of a double diaphragm sh...

By: Ingo Stotz, Grazia Lamanna, Harald Hettrich, Bernhard Weigand, and Johan Steelant

Description: A double diaphragm shock tube facility for studying liquid-spray atomization and combustion-related phenomena at elevated pressures and temperatures is described. The present shock tube is specifically intended for the investigation of fundamental processes related to fluid disintegration and mixing under realistic engine conditions. Special features of the facility include a variable-area driver section to compensate for shock attenuation, a square test sec...

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Applied Physics Letters : The enhancement of ZnO nanowalls photoco...

By: F. Fang, D. X. Zhao, B. H. Li, Z. Z. Zhang, J. Y. Zhang et al

Description: 10 nm sized hexagonal CdS nanoparticles were decorated on the surface of well-aligned ZnO nanowall through a facile hydrothermal approach. The effects of CdS-cap layer on the optical and photoelectrical properties of ZnO nanowalls have been studied. It was found the CdS acted not only as a passivation layer to suppress the detrimental surface states of ZnO nanowalls, which reduced the deep-level emissions, but also as an interfacial carrier transport layer t...

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Physics of Fluids : Unsteady flow separation on slip boundaries

By: Francois Lekien and George Haller

Description: We derive analytic criteria for the location and angle of unsteady particle separation and reattachment in two-dimensional flows with free-slip boundary conditions. Our wall-based criteria show that, in general, fluid breakaway from the boundary takes place at locations different from either instantaneous or averaged stagnation points. Indeed, for time-varying flows, separation does not occur along a free streamline or along an average free streamline. We ap...

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The Journal of Chemical Physics : Effect of solvent polarization o...

By: Egor Vladimirov, Anela Ivanova, and Notker Rösch

Description: The solvent contribution λs to the reorganization energy of electron transfer can be estimated from averages of the potential energy gaps between neutral-pair and ion-pair states over an ensemble of structures generated from molecular dynamics simulations. Invoking a Marcus-type two-sphere model for charge separation and recombination in an aqueous environment, we explored the effect of a polarizable force field and noted a strong reduction of λs (by ∼ 45%) ...

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Applied Physics Letters : An in situ electrical study on primary h...

By: Chikai Lin, Zhenzhen Yang, Tao Xu, and Yufeng Zhao

Description: Primary hydrogen spillover has been studied using a unique electrical method. We observed that at ambient temperature, when a discontinuous nanogranular Pd film is on the top of an amorphous carbon film, the electrical conductance of the carbon film decreases in pressurized hydrogen. In comparison, in the absence of this Pd layer, the conductance of the carbon film remains unchanged in pressurized hydrogen. The observed decrease in the current in the Pd/carb...

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Physics of Plasmas : Toroidal equilibria in spherical coordinates

By: K. H. Tsui

Description: The standard Grad–Shafranov equation for axisymmetric toroidal plasma equilibrium is customary expressed in cylindrical coordinates with toroidal contours, and through which benchmark equilibria are solved. An alternative approach to cast the Grad–Shafranov equation in spherical coordinates is presented. This equation, in spherical coordinates, is examined for toroidal solutions to describe low β Solovev and high β plasma equilibria in terms of elementary functions.

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Journal of Applied Physics : Particle size effect on strength, fai...

By: E. B. Herbold, V. F. Nesterenko, D. J. Benson, J. Cai, K. S. Vecchio et al

Description: The variation of metallic particle size and sample porosity significantly alters the dynamic mechanical properties of high density granular composite materials processed using a cold isostatically pressed mixture of polytetrafluoroethylene (PTFE), aluminum (Al), and tungsten (W) powders. Quasistatic and dynamic experiments are performed with identical constituent mass fractions with variations in the size of the W particles and pressing conditions. The relat...

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Review of Scientific Instruments : A sensitive and high dynamic ra...

By: S. Krishnan, K. S. Bindra, and S. M. Oak

Description: We report the design of a cost effective, highly sensitive cw laser power meter with a large dynamic range based on a photodiode. The power meter consists of a photodiode, a current to voltage converter circuit, an offset balancing circuit, a microcontroller, an analog to digital converter, reed relays, and an alphanumeric liquid crystal display. The power meter can record absolute laser power levels as low as 1 pW. The dynamic range measured with a cw laser...

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Biblioteca Hispanica : Course of Natural History, Physiology and H...

By: Ramon Vigil Martinez
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Journal of Applied Physics : Optically driven fluid flow along arb...

By: Franz M. Weinert and Dieter Braun

Description: We show how fluid can be moved by a laser scanning microscope. Selected parts of a fluid film are pumped along the path of a moving warm spot which is generated by the repetitive motion of an infrared laser focus. With this technique, we remotely drive arbitrary two-dimensional fluid flow patterns with a resolution of 2 μm. Pump speeds of 150 μm/s are reached in water with a maximal temperature increase in the local spot of 10 K. Various experiments confirm ...

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Journal of Applied Physics : Green light emission from InGaN multi...

By: W. Feng, V. V. Kuryatkov, A. Chandolu, D. Y. Song, M. Pandikunta et al

Description: Selective area epitaxy has been used to grow pyramidal GaN stripes, followed by InGaN multiple quantum well (MQW) structures, in order to produce long-wavelength green light emission. Stripes oriented along 〈110〉 produce smooth {101} sidewall facets. The room-temperature optical properties are investigated by cathodoluminescence spectroscopy using a scanning electron microscope. MQWs grown in unmasked reference regions exhibit emission at 450 nm. The stripe ...

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Physics of Plasmas : Cross-point coronal plasma dynamics in two- a...

By: R. E. Madden, S. C. Bott, D. Haas, Y. Eshaq, U. Ueda et al

Description: Studies of the late time diode gap formation in two- and four-wire tungsten x-pinches using an 80 kA, 50 ns current pulse are presented. Quantitative measurements of the coronal plasma density are recovered using interferometry simultaneously with laser shadowgraphy. Axial expansion of the gap occurs at ∼ 106 cm/s for both two- and four-wire systems and is likely to be driven by an axial J×B force resulting from radial current flow in the plasma minidiode “e...

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